It's a must-have tool for anyone serious about crafting the perfect espresso. It works by evenly spreading coffee grounds, creating a level and consistent coffee bed that promotes optimal extraction. This precision helps prevent channeling and uneven tamping, which can lead to bitter or weak shots. Detail: Material: 304 Stainless Steel Size: Small-350ml: 7.8cm x 11.5cm x 10cm Large-450ml: 8.5cm x 12cm x 11cm